It obliquely answers the “it was hotter than this millions of years ago, so what?” by insisting that human timescales are the ones that matter – for us humans. It’s amazing to me that people find this argument compelling, perhaps it’s because it’s impossible to really comprehend million-year timescales? If the last time the Earth was as hot as it’s projected to be was when the continents were in different places, coastlines were unrecognizable and the Earth was populated with vastly different species, that’s not exactly reassuring!